How good is Ubuntu Suitable for Lenobo G510. I am planning to buy a new laptop and G510 falls in my affordable range. There I am wondering which spec to take? the one with ATI card or not? Is there any problem with Wifi and Graphics Driver?

I need a laptop to use Ubuntu on a daily basis for work and entertainment. If Lenovo G510 is not suitable, what else is? Budger 45k INR.

Wired Ethernet needed latest hardware drivers to work, so I just use the LTS Enablement Stack (sounds worse than it is - it needs just 1 line in the console and a reboot). See this link.
The HDMI port needs to be enabled in the BIOS, which I believe mine is (BIOS V3.7)

The fixes are really quick and easy to implement.

I am pleased at the speed of this machine (I don't run Windows on it). It has the i7-4700MQ CPU running at 2.4Ghz and a 1TB hybrid disk with 8GB cache. I use it for photo and video editing, video creation from stills and document creation (with large graphics). All can be resource hungry!

I have the version with i3-4000m cpu, without dedicated graphics. Runs well with Windows 7 x64.

Ubuntu 14.04 (actually haven't tried it with the main edition, only Xubuntu, Kubuntu and Ubuntu Gnome ed.), in both x32 and x64, experiences random freezes, that can be solved only by a hard reboot. Ctrl-Alt-Backspace doesn't work, even if enabled, nor does Ctrl-Alt-F1 to switch to another virtual terminal. I saw a post where someone claimed it happens mainly when downloading. It may be so, but I'm unsure (last time, under gnome shell, it did). Maybe the newer bios update, the one for Windows 8.1, from the Lenovo site solves the issue. I haven't tried it.

Also, the Broadcom wireless requires proprietary drivers - they can be easily installed from the Additional Drivers GUI (or something similar) if connected to a wired network. If not, the can be installed from the bcmwl-kernel-source* package present in the pool directory on the installation medium (where there are also its prerequisites, in various subdirectories).